In Situ STM Study of Chloride Adsorption on Cu(110) Electrode in Hydrochloric Acid Aqueous Solution

Electroplated Copper Additives for Advanced Packaging: A Review

Acid copper electroplating stands as a core technology in advanced packaging processes, facilitating the realization of metal interconnects, bumps, vias, and substrate wiring between transistors. The deposition quality of copper interconnect materials has a crucial impact on the final performance of chips, directly influencing their yield, reliability, and stability. In this intricate process, additives play a pivotal role in regulating the deposition quality and behavior of metal copper. This mini-review comprehensively summarizes the recent research progress in the field of electroplating copper additives for advanced packaging, both domestically and internationally, delving into the types and mechanisms of various additive molecules, including accelerators, inhibitors, and leveling agents. Through in-depth research on these additives, we gain a profound understanding of their specific roles in the electroplating process and the intricate interaction mechanisms among them, providing theoretical support for optimizing the electroplating process. Furthermore, this mini-review also delves into a thorough analysis of the current issues and challenges facing acid copper electroplating, exploring the key factors that constrain the further development of electroplating copper technology. Based on this analysis, we propose several potential solutions and research directions, offering crucial references for the development and application of electroplating copper additives in advanced packaging. In conclusion, this mini-review aims to provide a comprehensive perspective and profound understanding of the development and application of electroplating copper additives through a review and analysis of recent research progress, ultimately aiming to promote the further advancement of advanced packaging technology.

First-principles study of coadsorption of Cu2+ and Cl− ions on the Cu (110) surface

Free energy of adsorption for the most stable phases predicted by DFT calculations as a function of electrode potential.

Structures, electronic properties and stability phase diagrams for copper(i/ii) bromide surfaces

This study presents a comprehensive periodic slab DFT investigation into structures, electronic properties and thermodynamic stability of all plausible terminations of CuBr and CuBr₂ surfaces. We find that surfaces terminated with negatively charged bromine atoms tend to be more stable if they are accompanied by significant relaxation.

Chloride-induced morphology transformations of the Cu(110) surface in dilute HCl

Morphological changes of a bare Cu(110) substrate in 10 mM HCl aqueous solution have been studied using cyclic voltammetry (CV), electrochemical scanning tunneling microscopy (EC-STM), and reflectance anisotropy spectroscopy (RAS). At cathodic potentials more positive than the hydrogen evolution reaction, a bare copper surface (1 × 1) structure is found by EC-STM. At anodic potentials more negative than the copper(II) dissolution reaction, a furrowed structure is found. The governing factor that rules Cu(110)-Cl interface processes is discussed as an interplay among Cl(-) adsorption/desorption, the dynamic rearrangement of the surface atoms on the substrate, and strain in order to reduce the surface energy. The information provided by EC-STM and RAS complements that of CV, supplies detailed information on the surface morphology, and correlates peaking Faraday currents to structural modifications. Furthermore, RAS and EC-STM show changes in the surface appearance in a potential range where no specific charge transfer is observed. CV indicates that the Cu(110) surface chemistry compares much better to that of amorphous Cu than to that of the more stable (100) and (111) surfaces, respectively.

The structures and thermodynamic stability of copper(ii) chloride surfaces

This study examines the structures of all plausible terminations of CuCl₂ surfaces and assesses their thermodynamic stability under practical operational conditions, relevant to the role of CuCl₂ as the most crucial chlorination catalyst in combustion systems.